Boiler



Aug. 29, 1933. D F; ,-LGOUR 1,924,209

` BOILER Original Filed Oct. 15, 1930 2 Sheets-Sheet l Allg. 29, 1933- D.-F. KILGoUR 1,924,209

BOILER Original Filed Oct. 13, 1930 2 Sheets-Sheet 2 Patented Aug. 29, 1933 PATENT OFFICE BOILIi'R Dwight F. Kilgour, Lexington, Mass.

Application October, 13, 1939, Serial No. 488,254 Renewed May 25, 1933 s claims. (c1. 12a-121) My invention relates to liquid heaters and vaporizers, for example, hot water and steam boilers. The invention will be best understood from the following description when read in the light of the accompanying drawings of one embodiment of the invention, the scope of which latter will be more particularly pointed out in the appended claims.

Fig. l is a vertical, longitudinal section of a boiler constructedaccording to the invention, with parts broken away, said section being a development taken on the line 11 of Fig. 2;

Figs. 2 and 3 respectively are sections on the lines 2-2 and 3--3 of Fig. 1;

Fig. 4 is a section on the line 4 4 of Fig. 2 on an enlarged scale showing a detail; and

Fig. 5 is a section corresponding to Fig. 4 showing a modified form of furnace.

Referring to the drawings, the boiler proper comprises a lower compartment or main water heating chamber 1 and an upper compartment or secondary water heating chamber 3, which compartments, in the particular embodiment of 25, the invention illustrated, are formed as separate containers in superimposed relation so as to provide, in connection with the casing 5, a smoke box or combustion chamber 7. As shown, the lower compartment l has the lateral cylindrical wall 9 closed at its upper and lower ends by the substantially ilat heads 11 and 13 respectively, while the upper compartment 3, which preferably is of much less height than the lower compartment, has the lateral cylindrical wall closed at its upper and lower ends by the substantially flat heads l5 and 17 respectively.

In the present embodiment of the invention, the heating medium, for example, hot products of combustion, is passed upward through the low- 40. er compartment l by flue means, which latter herein is in the form of a plurality of vertically disposed nre tubes 19 grouped adjacent the vertical axis of said compartment, said tubes secured to the heads 1l and 13 in any convenient manner, for example, by welding.

As shown, the lower compartment 1 is provided with a group of vertical fire tubes 21, distributed in spaced relation circumferentially of said lower compartment adjacent the lateral wall of the latter. The tubes 21 serve to conduct the combustion products from the smoke chamber 7 downward through said compartment and to discharge said products into the annular smoke box or ilue 55 23, which latter conveniently is connected to a stack or other draft producing means by a smoke pipe 25. The tubes 19 and 21 are preferably of the same diameter, but the number of tubes in each group of tubes is preferably such that the total cross-sectional area of the group of tubes 21 is less than that of the group of tubes 19, so 60 as to compensate for the decrease in volume of the combustion products caused by the cooling of the same in their passage through the boiler. As illustrated, the upper portion of the lower compartment 1 is placed in fluid communication 65 with the lower portion of the upper compartment 3 by a plurality of tubes or nipples 27, the lower head 15 of the upper compartment and the upper head 13 of the lower compartment for this purpose being provided with aligned perforations 29 with which opposite ends of the tubes or nipples register. As shown, for securing the tubes 2'7 to the respective heads 13 and 15, the

tubes are provided with flanges 31 (Fig. 4) preferably integrally formed therewith, which iianges are bolted to said heads by tap bolts 33. Preferably, for securing suilicient thickness of metal for satisfactory engagement by the threads of the bolts 33, the heads 13 and 15 are thickened adjacent the performations 29 by use of annular 30 pads 35 concentric with said perforations, which pads may be welded or otherwise secured to said heads. Conveniently, to permit expansion and to compensate for slight inaccuracies in manufacture, the flanges 31 of the tubes 27 are joined to 85 the bodies of the tubes by portions 36 of suilicien curvature to be somewhat resilient.

It will be understood that the water heated in the lower compartment 9 tends strongly to rise to the top of said compartment, and, in the present boiler, such water will flow through the tubes 27 and be discharged into the upper compartment 3, where, if the boiler is arranged for generating steam, the water will be freed from the steam, which latter will collect in the socalled steam space above the water lever 37 in said upper compartment, and from which space it may be withdrawn for use by one or more steam pipes 39. In this connection, it will be observed `that the hot products of combustion in the smoke chamber 7 heat the water in contact with the lower head 15 of said compartment, which water tends to rise. For preventing this rising water from interfering with the downward currents of water discharged into the upper compartment through the pipes 2'7, the lower head of said compartment is shown as provided with short, upstanding nipples 4l, welded to or otherwise carried by said head, said nipples being in registry with the perforations 29, which con- `water against the lower head of the boiler.

struction causes the water from the pipes 27 to be discharged into the upper compartment above the lower head of the latter. 'This construction also provides that, when the boiler is used as a. steam generator, the steam in the water discharged into the upper compartment through the pipes 27 will be allowed to separate from such water at points materially above the lower head of said compartment, with the result that such separation of steam occurs at points above those at which is separated the steam formed in the hot In the absence of the nipples 41 most of the steam generated would be separated from the water adjacent the lower head 15, which, due to the consequent great amount of steam at this point,

would cause a violent ebullition of the water, and' thus cause so-called priming or the vformation of unduly wet steam.

As shown, arranged alternately with the tubes 27 are similar tubes 43, which at their lower ends register with the upper ends of tubes 45, the latter welded or otherwise secured at said ends to the upper head 13 of the lower compartment of the boiler and extending downward through said compartment to adjacent the lower head 1l thereof.

By reason of the foregoing construction, the water which rises in the lower compartment and is discharged into the upper compartment by the tubes 27 is returned to the lower portion of the lower compartment without interference from the rising currents of water in said lower compartment. With a boiler constructed as herein described, the heating effect on the water is very great adjacent the central part of the lower head of the lower compartment, with the result that steam is rapidly formed in the boiler at this point. This tends to cause the lower end portions of -the tubes 19 and the adjacent parts of the head 11 to have a mixture of steam and water in contact therewith, with a pronounced tendency of these parts of the boiler to burn out. However, by use of the circulatory system comprising the tubes 27, 43 and 45, a large amount of relatively low temperature water is discharged from the lower ends of the tubes 45 for eliminating the effect just mentioned, with the result that burning out of the lower ends of the boiler tubes 19 and the central part of the head 11 is eliminated, and further, due to the rapid circulation produced, the capacity of the boiler for rapidly generatmg steam is considerably increased, without, as above described, causing primingor the production of unduly wet steam. y

As hereinafter more fully described, the boiler setting provides an annular wall 47 on which the lower head 11 of the lower compartment 9'rests for supporting the boiler proper. There is a minimum amount of steam generated from the water in contact with the annular portion of the lower head 1l in Contact with the wall 47, with the result that the tendency to cause ascending currents of water at this portion of theboiler is not especially pronounced. Preferably, the lower ends of the tubes 45 are above this portion of the lower head 11, so that the interference of ascending currents of water with the water discharged from the lower ends of the tubes 45 will be at a minimum. This materially improves the rapidity of circulation.

With the boiler constructed as above described, it will be observed that provision is made for preventing excess mixtures of steam and water in contact with all parts of the boiler exposed to hot combustion products, with the result that all such parts of the boiler in effect are substantially in contact with water. This effect at the lower portion of the lower compartment of the boiler is due largely to the circulatory system provided, and because of it the boiler can be made of sufiicient steam generating capacity while keeping the height of the boiler relatively low. In this connection, it will be observed, that in the absence of this circulatory system, it would be impractical to heat the water rapidly at the lower portions of the lower compartment, because, the attempt to secure such rapid heating at said portions, under these conditions, would cause the central part of the lower head 13 and lower end portions of the fire tubes 19 to be in contact with water mixed with a large amount of steam, with the result that burning out of the lower ends of said tubes would occur; and, therefore, in the absence of the circulatory system, to secure the same aggregate heating capacity of the boiler without burning out the lower ends of the tubes 19, a less number of said tubes would be employed to reduce the heating effect on the water at the lower central portion of the boiler, and said tubes would be made longer to secure the desired aggregate heating capacity, with the consequent result that the height of the boiler would be increased. Expressed in a mathematical sense, the present construction provides, therefore, that the amount of heat imparted to the water per unit of height of the boiler can be increased over that possible with boilers as heretofore constructed, and it will be understood that this feature is of considerable practical importance in designing boilers for installation in buildings, especially where the boilers are employed in connection with heating systems in small dwellings.

As herein illustrated, the boiler setting, the upper portion of which is formed to provide the annular wall 47 hereinbefore referred to, comprises the annular outer wall 49 which may be of common fire-brick, and an adjacent inner wall 51 of higher heat refractory nre-brick, the parts of which latter exposed to combustion products are lined with still higher heat refractory material 53.

Herein, the boiler setting at its lower central portion is formed to provide a re-pot which, in the form shown, is particularly adapted for burning liquid or pulverized solid fuel, but, as will be understood by those skilled in the art, may be suitably formed for receiving a grate on which coal or other solid fuel is burned. The space 57 of the boiler setting surrounded by the annular wall 47 is herein connected to an opening 59 in the roof of the fire-pot 55 by an upwardly fiaring ue passage 61, said opening 59 preferably being of less diameter or cross-sectional area than the fire-pot. As a result of this construction, the ignited, partially consumed gases rising from the fire-pot and discharging into the upwardly ared iiue 61 through the throat aiforded by the opening 59, are given a whirling action in said flue 61, which I have found results in complete and perfect combustion of the fuel gases. The gases which rise through the central group of fire tubes 19 and discharge into the combustion chamber 7 have a decreased velocity through said chamber due to its large cross-sectional area, which acts to secure a considerable heating effect on the parts of the boiler which define said chamber, with the result that the maximum heat is absorbed by the water from the combustion gases by the time thelatter are discharged into the smoke box 23. i

As illustrated in Fig. 3, an oil burner'of a con.- ventional type is provided for heating the boiler. As shown, this burner comprises an air nozzle 63, which is supplied with air by a Ian or pump 65 driven by an electric or other motor 67, the air nozzle having an associated oil nozzle 69, herein shown as coaxially arranged therewith, so that a mixture oi.' air and oil is discharged into the tire-pot through the opening 71 with which said air nozzle communicates. In Fig. 3 the nozzlev 63 is arranged to project the combustible mixture into the repot diametrically of the latter. In some instances, especially with s-called long flame burners, improved results will be secured by positioning the nozzle 63 in oil-center relation to the fire-pot, as for example as shown by Fig. 5, with the result that the ilame and combustion products are given a whirling motion prior to entering the upwardly flaring iiue 61, thus accentuating the eilect of the latter.

Herein, for improving combustion. the suction pipe 73 of the fan is in communication with one end of an arcuate chamber 75 which is concen-A tric with and surrounds the major portion of the nre-pot, so that said fan draws heated air from said chamber and discharges it into the tire-pot through the opening 71. As shown, atmospheric airis supplied the air heating chamber 75 through an opening 77 at the end of said chamber opposite the end thereof with which the suction pipe 73 communicates.

'Ihe boiler setting, furnace, and combustion apparatus herein described from the subject matter of my co-pending application Serial No. 561,872, filed September 9, 1931, which is a division of this application.

It will be understood that within the scope of the invention wide deviations may be made from the embodiments thereof herein described without departing from the spirit of the invention.

I claim:

1. A boiler having, in combination, means formed to provide upper and lower water containers with'a smoke box between them, vertical re tubes grouped around the medial axis of said lower container and extending through the latter and opening into said smoke box, a plurality of spaced water conducting tubes connecting the upper portion of said lower container with the lower portion of said upper container, and a plurality of water conducting tubes spaced from said ilrst mentioned water conducting tubes and distributed in the space between said group of nre tubes and the lateral walls of said lower container, said last mentioned water conducting tubes connecting the lower portion of said upper container with the lower portion of said lower container and being arranged to conduct water from said upper container and discharge it adjacent the lower tube sheet oi' `said lower container at a plurality oi' points between said group of iire tubes and the lateral walls of said lower container, whereby relatively cold water is caused to ow across said tube sheet inwardly from the exterior of said group of fire tubes and the ascending current of relatively hot water caused by said tire tubes is prevented from materially heating the down-flowing water in said last mentioned Water conducting tubes.

2. A boiler having, in combination, means formed to provide upper and lower water containers with a smoke box between them, vertical re tubes grouped around the medial axis of said lower container and extending through the latter and opening into said smoke box, a plurality of straight, vertical, spaced water conducting tubes connecting the upper portion of said lower container with the lower portion of said upper con,- tainer at points slightly above the bottom wall of the latter, and a plurality of straight, vertical water conducting tubes spaced from said ilrst mentioned water conducting tubes and distributed in the space between said group of iire tubes and the lateral walls of said lower container, said last mentioned water conducting tubes connecting the lower portion o! said upper container with the lower portion of said lower container and being arranged to conduct water from said upper container and discharge it adjacent the lower tube sheet of said lower container at a plurality oi points between said group oi' ilre tubes and the lateral walls of said lower container, whereby relatively cold water is caused to flow across said tube sheet inwardly from the exterior of said group of fire tubes and the ascending current of relatively hot water caused by said iire tubes is prevented from materially heating the down-flowing water in said last mentioned water conducting tubes.

3. Apparatus of the character described having, in combination, a vertical iire tube boiler having upper and lower tube sheets and central and lateral groups of vertical fire tubes connecting said tube sheets, a drum above said boiler in spaced relation thereto to form a space for placing the upper ends of said groups oi' tubes in com, munication, a set of straight, vertical water tubes opening through the upper tube sheet of said boiler at points between said central and lateral groups of nre tubes and extending into said drum through the lower wall thereof to points slightly above said wall, a second set of straight, vertical Water tubes arranged alternately with the tubes of said first mentioned set and opening through the lower wall of said drum and extending into said boiler through the upper tube sheet thereof to points slightly above the lower tube sheet thereof, said last mentioned water tubes being arranged to conduct water from said drum and discharge it adjacent said lower tube sheet at a plurality of points between said central and lateral groups of fire tubes, whereby relatively cold water is caused to ilow across said tube sheet inwardly i'rom the exterior of said central group of re tubes and the ascending current of relatively hot water caused by said fire tubes is prevented from materially heating the down-flowing water in said last mentioned water conducting tubes.

4. Apparatus of the character described having, in combination, a vertical type re tube boiler having a centrally positioned set of Vertical lire tubes and an outer set of vertical fire tubes, the latter distributed in spaced relation to said first mentioned set, a boiler setting comprising an annular wall on the top of which said boiler rests, said sets of tubes opening on the lower head of said boiler at opposite sides of said wall, a iiue extending about said wall in communication with said outer set of tubes, a ue surrounded by said wall for conducting products of combustion to said centrally positioned set of tubes, a drum above said boiler in spaced relation thereto, vertical water tubes connecting the upper portion of said boiler to the lower portion of said drum, and vertical tubes connecting the lower portion of said drum to the lower portion of said boiler and arranged for discharging water 150 from said drum downwardly against that portion o! the lower wall of said boiler which is directly above said annular wall.

5. Apparatus of the character described having. in combination, a vertical type iire tube boiler having a centrally positioned set of vertical ilre tubes and an outer set ot vertical nre tubes, the latter distributed in spaced relation to said lrst mentioned set, a boiler setting comprising an annular wall formed interiorly thereof to provide an upwardly aring throated flue, on the top of which wall said boiler rests, said sets of tubes opening on the lower head of said boiler at opposite sides o! said wall, a flue extending about said wall in communication with said outer set of tubes, a drum above said boiler in spaced relation thereto, vertical water tubes connecting the upper portion of said boiler to the lower portion of said drum, and vertical tubes connecting the lower portion of said drum to the lower portion of said boiler and arranged for discharging water from said drum downwardly against that portion of the lower wall of said boiler which is directly above said annular wall.

6. A boiler having, in combination, means formed to provide upper and lower water containers with a smoke box between them, a central group of vertical ilre tubes situated addacent the medial axis of said lower container, a second group ot iire tubes distributed adjacent the lateral walls of said lower container in spaced relation to said ilrst mentioned group, a plurality of spaced water conducting tubes connecting the upper portion of said lower container at points between said groups of fire tubes with the lower portion oi.' said upper container, and a plurality ot water conducting tubes spaced from the nrst mentioned water conducting tubes and distributed in the space between said groups of tire tubes, said last mentioned water conducting tubes connecting the lower portion oi' said upper container with the lower portion oi.' said lower container and being arranged to conduct water from said upper container and discharge it adjacent the lower tube sheet of said lower container at a plurality of points between said groups of nre tubes, whereby relatively cold water is caused to ilow across said tube sheet inwardly from the exterior o! said central group of fire tubes and the ascending current o! relatively hot water caused by said ilre tubes is prevented from materially heating the down-flowing water in said last mentioned water conducting tubes.

DWIGHT F. KILGOUR. 

